1. Field of the Invention
The present invention relates to a mechanism for guiding slides of single or multi-slide mechanical presses.
2. Description of the Related Art
A gib is a mechanism in stamping or drawing press to adjust a reciprocating slide in a direction substantially normal to its reciprocating movement. Prior presses have had gibs that utilized wear plates along the outside edges of the slide and other press portions to control the clearances between the slide and press frame, in single slide presses and between one slide and another in a multi-slide press. These gibs have been used to adjust the running clearance of the slide.
Prior gibs have contained elastomeric seals to seal between the gib mounting surface and slide to prevent lubrication from passing from the gib, down the slide, and on to the parts being stamped on the press. Other ways of preventing oil from contacting product included sheet metal gutters and the like.
Known problems with elastomeric seals are that at times they do not seal properly and leak. Actually, for proper operation of these types of seals, normally a small amount of lubrication, (one or two drops) must pass by the seal to thereby cause the seal to fully seal against further leakage. In some production environments, such as food beverage containers, i.e., soft drink cans, beer cans, and like, even these one or two drops of lubrication contacting the formed cans is unacceptable. Leakages of lubrication fluid necessary for proper elastomeric seal operation have caused scraping of entire production runs of such beverage cans with an associated large cost.
Maintenance requirements on elastomeric or O-ring seals on these gibs is necessary since the seals have rubber or flexible wiper portions that mechanically wear over time. This mechanical wear causes the seals to eventually fail and leak. Removal and replacement of these seals necessitate the press to be placed off-line and disassembled to obtain service access to the gib mount assembly and elastomeric seal seat.
Depending on the number of slides a press has and its particular type of guiding, i.e., four point, six point, eight point, and others, the press may have varied numbers of these gib assemblies. The more gib assemblies with elastomeric seals, the higher the likelihood of a lubrication leak and the more need of service.
Other problems with gibs and associated seals is use of O-rings as seals. These seals required circular or annular mounts to seal i.e., locations without sharp corners. This necessitated that the areas sealed against need to be cylindrical shaped, rod shaped, or at least some shape with a curved or circular cross-section. These types of O-ring seals could not seal at interior or exterior corners since the seal would have to be slit and attached to another seal at the discontinuous point of the corner.
What is needed in the art is a gib mechanism for a press that seals against lubricant leakage without using elastomeric seals that eventually leak.